Trump pledged during his campaign to “cancel” the deal, but delayed a decision for months amid a split in the administration on the issue. But in recent weeks, the camp opposing the accord apparently convinced the president to abandon it ― despite few political advantages and harsh economic and diplomatic consequences.

Under the terms of the deal, the U.S. cannot officially withdraw until November 2019. But even an announcement that the country is looking to leave the deal shows that the White House has no plans to meet earlier targets for slashing greenhouse gas emissions.

That much was already clear. In March, Trump ordered the Environmental Protection Agency to review the Clean Power Plan, a sweeping regulation passed by former President Barack Obama to limit emissions from the utility sector, by far the country’s biggest emitter. The policy was already stayed by the Supreme Court in February 2016 as a result of a lawsuit filed by former Oklahoma Attorney General Scott Pruitt, who is now Trump’s head of the EPA. Without the Clean Power Plan, the U.S. wouldn’t even come close to meeting its goals laid out in the 2015 Paris Agreement.

Trump vowed to jumpstart the U.S. economy by eliminating environmental regulations he blamed for holding back companies. In particular, he positioned himself as a staunch advocate for fossil fuels, nixing climate change funding from his proposed budget and scrapping rules that discourage pollution and boost renewable energy. But, somewhat ironically, major oil, gas and coal companies ― along with a plethora of other big corporations ― urged Trump to keep the U.S. in the Paris Agreement.

Environmental groups have little legal recourse given that the Obama administration bypassed the Senate to ratify the deal, arguing it did not constitute a treaty. But the Trump administration is still required to regulate carbon dioxide emissions as a public health threat under a 2007 Supreme Court ruling. How it plans to fulfill that legal responsibility that is unclear.

Quitting the Paris Agreement strikes a major diplomatic blow to the U.S. Only war-torn Syria and Nicaragua, the second-poorest country in the Western Hemisphere, are not included in the accord. Retreating from the agreement, which the U.S. took a lead role in brokering, brands the nation as a “rogue country” and a “climate pariah,” diplomats said. Without a seat at the table, the U.S. loses leverage over policy action on global warming, and cedes influence to rival superpower China, which has vowed to support poorer countries’ efforts to adapt to climate change.

“Who cares?” Myron Ebell, a top climate change denier who led Trump’s EPA transition team, told HuffPost on Tuesday ahead of the announcement. “If countries are moving in the wrong direction, I don’t think the leader of that movement has much to look forward to. It seems to me that President Trump has a chance to not only turn the direction of the country around but the direction of the world around. Good luck to China.”

Who cares? … It seems to me that President Trump has a chance to not only turn the direction of the country around but the direction of the world around.Myron Ebell, a top climate change denier who led Trump’s EPA transition team

Yet few credible, peer-reviewed scientists believe manmade climate change isn’t a major problem, and a growing number of investors are already pouring money into transforming the energy economy.

The economic effects of leaving the Paris Agreement would likely be devastating. The U.S. is poised to lose access to fast-growing clean energy markets as Europe, India and China gain major footholds in an industry estimated to be worth $6 trillion by 2030. Countries that tax emissions could now put a tariff on American-made imports, complicating Trump’s plans to reclaim the U.S. mantle as a top manufacturing hub.

“It’s very clear that the energy economy is heading in a direction that, if you don’t engage with climate change, you’re going to miss out on a large number of jobs that have already emerged,” David Waskow, director of the World Resource Institute’s international climate program, told HuffPost before the announcement. “Withdrawing and retreating would have very negative implications for the U.S. economically.”

It’s unclear what Trump gains politically from the withdrawal. The deal had overwhelming support. Sixty-one percent of Americans said the country should remain in the deal, while just 17 percent support withdrawing and 21 percent weren’t sure, according to a HuffPost/YouGov poll conducted earlier this month. And more than 400 U.S. cities, 37 states, 800 universities and nearly half of all Fortune 500 companies have already set their own clean energy and emissions targets.

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